The Validation and Accuracy of Wearable Heart Rate Trackers in Children With Heart Disease: Prospective Cohort Study.

Background: Wearables are increasingly used in pediatric cardiology for heart rate (HR) monitoring due to advantages over traditional HR monitoring, such as prolonged monitoring time, increased patient comfort, and ease of use. However, their validation in this population is limited.

Objective: The objective of this paper was to assess HR accuracy and validity from 2 wearables, the Corsano CardioWatch bracelet and the Hexoskin smart shirt, in children attending the pediatric cardiology outpatient clinic, exploring factors that influence accuracy, the Hexoskin shirt's arrhythmia detection efficacy, and patient satisfaction.

Methods: Children with an indication for 24-hour Holter monitoring were equipped with a 24-hour Holter electrocardiogram (ECG; gold standard), together with both wearables. HR accuracy was defined as the percentage of HRs within 10% of Holter values, and agreement was assessed using Bland-Altman analysis. Subgroup analyses were conducted based on BMI, age, and time of wearing, among other factors. The association between accelerometry (expressed in gravitational units, g) and HR accuracy was analyzed to assess the impact of bodily movement on measurement accuracy. A blinded pediatric cardiologist analyzed Hexoskin shirt data for rhythm classification. Patient satisfaction was measured using a 5-point Likert scale questionnaire.

Results: A total of 31 participants (mean age 13.2, SD 3.6 y; n=14, 45% female) and 36 participants (mean age 13.3, SD 3.9 y) were included for the CardioWatch and Hexoskin measurements, respectively. Mean accuracy was 84.8% (SD 8.7%) for the CardioWatch and 87.4% (SD 11%) for the Hexoskin shirt. Hexoskin shirt accuracy was notably higher in the first 12 hours (94.9%, SD 7.4%) compared to the latter 12 (80%, SD 16.7%; P<.001). Higher accuracy was observed at lower HRs (low vs high HR: CardioWatch: 90.9%, SD 9.3% vs 79%, SD 10.6%; P<.001 and Hexoskin shirt: 90.6%, SD 14% vs 84.5, SD 11.8%; P<.001). Both wearables demonstrated good agreement in their HR measurement with Holter readings (CardioWatch bias: -1.4 beats per minute [BPM]; 95% limits of agreement [LoA] -18.8 to 16.0. Hexoskin shirt bias: -1.1 BPM; 95% LoA -19.5 to 17.4). HR measurement accuracy declined during more intense bodily movements. Correct classification of the Hexoskin's shirt rhythm recordings was achieved in 86% (31/36) of cases. Patient satisfaction scores were significantly higher for both the CardioWatch (median 3.8, range 3.5-4.3; P<.001) and Hexoskin shirt (median 3.7, range 3.0-4.0; P<.001) compared to the Holter (median 2.6, range 2.1-3.2).

Conclusions: The Corsano CardioWatch and Hexoskin shirt demonstrate good accuracy in pediatric HR monitoring and provide higher patient comfort than conventional monitoring. Both wearables show good agreement in relation to the gold standard device. However, measurement accuracy declines with increasing bodily movement and higher heart rates. More research is needed to explore the underlying causes for these inaccuracies and how to counteract them. The Hexoskin shirt also shows potential in arrhythmia detection. While further development is warranted, these wearables show promise in enhancing diagnostics, therapeutic monitoring, and patient safety in pediatric cardiology.